Structured Programming
Introduction
• Program:
– A program is a set of sequenced instruction to cause a
computer to perform particular operation or to solve the
given problem
• Programming:
– Process of developing such program is called programming
• Programmer:
– Person who does programming is called programmer
• Programming Language:
– The language that is used to develop the program is called
programming language
– “Programming languages are set of instruction used to
write a program”
– The language used to communicate with computer is
known as programming language
– program can be categorized based on how close to normal
speech they are, and thus how far from the computer’s
internal languages
Generation of languages
• Machine language or First Generation Language
• Assembly language or Second Generation Language
• Procedural language or Third Generation Language
• Problem Oriented Language or Fourth Generation Language
• Natural Language or Fifth Generation Language
ALGORITHM
• An algorithm is a process or set of rules to be followed in
calculations or other problem-solving operations, especially
by a computer
• Formally defined procedure for performing some calculation
• An effective procedure for solving a problem in a finite
number of steps
• An algorithm gives the step by step description of how to
arrive at a solution
Characteristics of algorithm
• Accuracy
• Clarity
• Not even a single instruction must be repeated infinitely
• After the algorithm gets terminated, the desired result must
be obtained
FLOWCHART
• A graphical or symbolic representation of a process
• Used to design and document complex processes to help the
viewers to visualize the logic of the process
• Provides a better understanding of the process and find flaws,
bottlenecks, and other less obvious features within it
• Usually drawn in the early stages of formulating computer
solutions
• When designing a flowchart, each step in the process is
depicted by a different symbol and is associated with a short
description
C Programming
• The C Language is developed for creating system applications
that directly interact with the hardware devices such as
drivers, kernels, etc.
• C programming is considered as the base for other
programming languages, that is why it is known as mother
language.
• It can be defined by the following ways:
– Mother language
– System programming language
– Procedure-oriented programming language
– Structured programming language
– Mid-level programming language
• C as a mother language
– Most of the compilers, JVMs, Kernels, etc. are written in C
language, and most of the programming languages follow
C syntax, for example, C++, Java, C#, etc.
• C as a system programming language
– A system programming language is used to create system
software.
– C language is a system programming language because
it can be used to do low-level programming (for example
driver and kernel
• C as a procedural language
– A procedural language specifies a series of steps for the
program to solve the problem.
– A procedural language breaks the program into functions,
data structures, etc.
• C as a structured programming language
– Structure means to break a program into parts or
blocks so that it may be easy to understand.
– In the C language, we break the program into parts using
functions. It makes the program easier to understand and
modify.
• C as a mid-level programming language
– C is considered as a middle-level language because
it supports the feature of both low-level and high-level
languages.
– A Low-level language is specific to one machine, i.e.,
machine dependent. It is machine dependent, fast to run.
But it is not easy to understand.
– A High-Level language is not specific to one machine, i.e.,
machine independent. It is easy to understand.
History of C
• C programming language was developed in 1972 by Dennis
Ritchie at bell laboratories of AT&T (American Telephone &
Telegraph), located in the U.S.A.
• Dennis Ritchie is known as the founder of the c language.
• It was developed to overcome the problems of previous
languages such as B, BCPL, etc.
• Initially, C language was developed to be used in UNIX
operating system. It inherits many features of previous
languages such as B and BCPL.
Features of C Language
1. Small
– C is a language of few words, containing only a handful of
terms, called keywords, which serve as the base on which
language’s functionality is built
2. Simple
– C is a simple language in the sense that it provides
a structured approach (to break the problem into
parts), the rich set of library functions, data types, etc.
3. Machine Independent or Portable
– Unlike assembly language, c programs can be executed on
different machines with some machine specific changes.
Therefore, C is a machine independent language.
4. Mid-level programming language
– supports the feature of both low-level and high-level
languages.
5. Structured programming language
– C is a structured programming language in the sense
that we can break the program into parts using functions.
So, it is easy to understand and modify.
First C Program
#include<stdio.h>
void main()
{
printf("Hello World");
}
• #include <stdio.h> includes the standard input output library
functions. The printf() function is defined in stdio.h .
• main() The main() function is the entry point of every
program in c language.
• printf() function is used to print data on the console.
